<template>
  <section class="msite">
    <!-- 首页头部 -->
    <HeaderTop :title="'加利福尼亚州'">
      <router-link class="header_search" slot="left" to="/search">
        <i class="iconfont icon-sousuo"></i>
      </router-link>
      <router-link class="header_login" slot="right" :to="userInfo._id ? '/userinfo': '/login'">
        <span class="header_login_text" v-if="!userInfo._id">登录|注册</span>
        <span class="header_login_text" v-else>
          <i class="iconfont icon-person"></i>
        </span>
      </router-link>
    </HeaderTop>
    <!--首页导航-->
    <nav class="msite_nav">
      <div class="swiper-container" v-if="categorys.length">
        <div class="swiper-wrapper">
          <div class="swiper-slide" v-for="(categorys, index) in categorysArr" :key="index">
            <a
              href="javascript:"
              class="link_to_food"
              v-for="(category, index) in categorys"
              :key="index"
            >
              <div class="food_container">
                <img :src="baseImageUrl+category.image_url">
              </div>
              <span>{{category.title}}</span>
            </a>
          </div>
        </div>
        <!-- Add Pagination -->
        <div class="swiper-pagination"></div>
      </div>
      <img src="./images/msite_back.svg" alt="back" v-else>
    </nav>
    <!--首页附近商家-->
    <div class="msite_shop_list">
      <div class="shop_header">
        <i class="iconfont icon-xuanxiang"></i>
        <span class="shop_header_title">附近商家</span>
      </div>
      <ShopList/>
    </div>
  </section>
</template>

<script>
import { mapState } from "vuex";
import Swiper from "swiper";
import "swiper/dist/css/swiper.min.css";
import HeaderTop from "@/components/HeaderTop/HeaderTop.vue";
import ShopList from "@/components/ShopList/ShopList.vue";
export default {
  data() {
    return {
      //首页导航图片地址
      baseImageUrl: "https://fuss10.elemecdn.com"
    };
  },
  mounted() {
    this.$store.dispatch("getCategorys");
    this.$store.dispatch("getShops");
  },

  computed: {
    ...mapState(["address", "categorys","userInfo"]),

    /*
      根据categorys一维数组生成一个2维数组
      小数组中的元素个数最大是8
       */
    categorysArr() {
      const { categorys } = this;
      // 准备空的2维数组
      const arr = [];
      // 准备一个小数组(最大长度为8)
      let minArr = [];
      // 遍历categorys
      categorys.forEach(c => {
        // 如果当前小数组已经满了, 创建一个新的
        if (minArr.length === 8) {
          minArr = [];
        }
        // 如果minArr是空的, 将小数组保存到大数组中
        if (minArr.length === 0) {
          arr.push(minArr);
        }
        // 将当前分类保存到小数组中
        minArr.push(c);
      });

      return arr;
    }
  },

  watch: {
    categorys(value) {
      // categorys数组中有数据了, 在异步更新界面之前执行
      // 界面更新就立即创建Swiper对象
      this.$nextTick(() => {
        // 一旦完成界面更新, 立即调用(此条语句要写在数据更新之后)
        // 创建一个Swiper实例对象, 来实现轮播
        new Swiper(".swiper-container", {
          loop: true, // 可以循环轮播
          // 如果需要分页器
          pagination: {
            el: ".swiper-pagination"
          }
        });
      });
    }
  },
  components: {
    HeaderTop,
    ShopList
  }
};
</script>

<style lang="stylus" rel="stylesheet/stylus">
@import '../../common/stylus/mixins.styl';

.msite { // 首页
  width: 100%;

  .msite_nav {
    bottom-border-1px(#e4e4e4);
    margin-top: 45px;
    height: 200px;
    background: #fff;

    .swiper-container {
      width: 100%;
      height: 100%;

      .swiper-wrapper {
        width: 100%;
        height: 100%;

        .swiper-slide {
          display: flex;
          justify-content: center;
          align-items: flex-start;
          flex-wrap: wrap;

          .link_to_food {
            width: 25%;

            .food_container {
              display: block;
              width: 100%;
              text-align: center;
              padding-bottom: 10px;
              font-size: 0;

              img {
                display: inline-block;
                width: 50px;
                height: 50px;
              }
            }

            span {
              display: block;
              width: 100%;
              text-align: center;
              font-size: 13px;
              color: #666;
            }
          }
        }
      }

      .swiper-pagination {
        >span.swiper-pagination-bullet-active {
          background: #02a774;
        }
      }
    }
  }

  .msite_shop_list {
    top-border-1px(#e4e4e4);
    margin-top: 10px;
    background: #fff;

    .shop_header {
      padding: 10px 10px 0;

      .shop_icon {
        margin-left: 5px;
        color: #999;
      }

      .shop_header_title {
        color: #999;
        font-size: 14px;
        line-height: 20px;
      }
    }
  }
}
</style>
